Correct Option: A

I : TCP allows full – duplex communication. This is TRUE statement. TCP is a full-duplex protocol; it allows both parties to send and receive data within the context of the single TCP connection.
II : TCP has no option for selective acknowledgments. This is FALSE statement. TCP may experience poor performance when multiple packets are lost from one window of data. With the limited information available from cumulative acknowledgments, a TCP sender can only learn about a single lost packet per round trip time. An aggressive sender could choose to retransmit packets early, but such retransmitted segments may have already been successfully received. A Selective Acknowledgment (SACK) mechanism, combined with a selective repeat retransmission policy, can help to overcome these limitations. The receiving TCP sends back SACK packets to the sender informing the sender of data that has been received. The sender can then retransmit only the missing data segments.
III : TCP work as a message stream. This is FALSE statement. In TCP, Data is read as a byte stream, no distinguishing indications are transmitted to signal message (segment) boundaries.